"That's interesting, because what we found is that there were actually not 365 days in the year; there were a few more."
「這很有趣,因為我們發現一年實際上不是365天,而是要比這個數多。」
You see, Earth's spin on its axis gradually slows down over time. The reduction is due to the friction from Earth's tides, which are driven by the moon's orbit.
你看,地球沿地軸自轉的速度隨時間而逐漸減慢。減慢的原因是月球軌道驅動的地球潮汐摩擦。
Back to that ancient clam. By measuring the rings on this mollusk's shell, the team was able to put a precise number on the history of this process. Seventy million years ago, the faster rotation of the Earth meant that there were just 23 and a half hours in a day.
說回古代蛤蜊。通過數這個軟體動物殼上的年輪,研究團隊能對這一過程的歷史長度給出一個精確的數字。7000萬年前,地球自轉速度較快,這意味著一天只有23.5小時。
And measuring more shells might reveal more information about our planet's past.
測量的貝殼越多,可能越能揭示有關地球歷史的更多信息。